A sludge electric dewatering system based on annular electric field

Abstract

The application discloses a sludge electric dewatering system based on a ring electric field, relates to the technical field of sludge electric dewatering, and first adds graphite to sludge through a sludge pretreatment unit, and carries out crushing and stirring to obtain a sludge mixture; most of free water and part of interstitial water are removed through a mechanical dewatering unit, so that the water content of the sludge is reduced; the initial sludge cake is conveyed to an electric dewatering unit by using a sludge cake conveying unit; and then the initial sludge cake is subjected to electric dewatering under a ring electric field through the electric dewatering unit, so that the water content of the sludge is further reduced, and sewage and dewatered sludge cake are obtained. The sludge pretreatment, the combination of mechanical dewatering and electric dewatering, the conveying belt conveying and the optimization design of multiple links such as the ring electric field are combined, so that efficient, energy-saving and environment-friendly sludge dewatering treatment is realized, and the application has significant progress significance.

Description

Technical Field

[0001] This invention relates to the field of sludge electro-dewatering technology, and more specifically to a sludge electro-dewatering system based on a ring-shaped electric field. Background Technology

[0002] With the acceleration of urbanization, sludge production continues to increase, making efficient and environmentally friendly sludge treatment an urgent problem to be solved. Traditional sludge treatment methods such as landfill and incineration not only occupy large areas but also easily cause secondary pollution. Therefore, developing economical and effective deep sludge dewatering technologies is particularly important.

[0003] Sludge electro-dewatering technology, as a novel deep sludge dewatering technology, boasts advantages such as high efficiency and rapid dewatering. This technology achieves solid-liquid separation based on electroosmotic flow generated on the surface of solid particles under an electric field, simultaneously removing free water, interstitial water, and some surface-bound water to achieve deep dewatering. Although electro-dewatering technology can reduce the moisture content of sludge to levels far exceeding those achieved by traditional mechanical dewatering, the relationship between energy consumption and processing capacity remains a challenge, with high energy consumption consistently hindering the development of electro-osmosis technology.

[0004] Traditional sludge conveying methods are also prone to low conveying efficiency due to improper equipment design or operation, which affects the overall treatment efficiency.

[0005] It is evident that existing technologies in the field of sludge dewatering treatment suffer from problems such as high energy consumption, limited processing capacity, complex operation, high equipment costs, and environmental and safety concerns. Therefore, improving the efficiency and quality of sludge dewatering treatment is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a sludge electro-dewatering system based on a ring electric field.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A sludge electro-dewatering system based on a ring-shaped electric field includes:

[0009] The sludge pretreatment unit is used to add graphite to the sludge and crush and mix it to obtain a sludge mixture.

[0010] A mechanical dewatering unit is used to mechanically dewater the sludge mixture to obtain an initial sludge cake;

[0011] A cake conveying unit is used to convey the initial cake to an electro-dehydration unit;

[0012] The electro-dehydration unit is used to electro-dehydrate the initial sludge cake under a ring electric field to obtain wastewater and dehydrated sludge cake.

[0013] Optionally, the sludge pretreatment unit includes a closed mixing tank, with a sludge inlet and a graphite inlet at the top, a sludge agitator at the bottom, and an outlet on the side of the mixing tank for introducing the sludge mixture into the mechanical dewatering unit through a pipeline.

[0014] Optionally, the mechanical dewatering unit includes a cylindrical extrusion cylinder, a discharge plate, and an extrusion plate;

[0015] The extrusion cylinder is a cylindrical structure with openings at the top and bottom, and several uniform openings are provided on the side wall. The inner wall of the side wall is lined with high-strength and high-permeability geotextile. The side wall is also provided with a sludge mixture inlet.

[0016] The unloading plate is disposed on the lower end face of the extrusion cylinder. The unloading plate is in contact with but not fixed to the lower end face of the extrusion cylinder. The unloading plate is also provided with several uniform openings and is lined with high-strength and high-permeability geotextile. The side of the unloading plate is connected to the first motor, and the first motor drives the unloading plate to move perpendicular to the axial direction of the extrusion cylinder.

[0017] The extrusion plate is disposed on the upper end face of the extrusion cylinder. One side of the extrusion plate is in contact with the sludge mixture inside the extrusion cylinder, and the other side is provided with a connecting rod. The connecting rod is connected to a second motor. The second motor drives the connecting rod and the extrusion plate to move axially along the extrusion cylinder, so that the extrusion plate extrudes the sludge mixture inside the extrusion cylinder, thereby achieving mechanical dewatering of the sludge mixture.

[0018] Optionally, the cake conveying unit is located below the mechanical dewatering unit and includes an opening platform and an opening conveyor belt;

[0019] The perforated conveyor belt is installed on the perforated platform, with the lower end face of the perforated conveyor belt in contact with the perforated platform and the upper end face covered with a high-strength, high-permeability geotextile.

[0020] Optionally, the electro-dehydration unit is an annular sleeve with an open bottom, the outer ring being the anode and the inner ring being the cathode. The upper end face of the annular sleeve is an insulating plate. One side of the insulating plate is fixedly connected to the outer and inner rings, and the other side of the insulating plate is connected to a third motor. The third motor drives the annular sleeve to move downward, so that the annular sleeve covers the initial mud cake and performs the electro-dehydration process.

[0021] Optionally, the lower end of the outer ring is an open structure, and the lower end of the inner ring is provided with a baffle. The baffle is fixed to the inner ring, and both the inner ring and the baffle are provided with several uniform openings and lined with high-strength and high-permeability geotextile.

[0022] Optionally, a water storage device is provided below the perforation platform to receive wastewater passing through the perforation conveyor belt and the perforation platform.

[0023] Optionally, the system further includes a wastewater treatment unit for recovering nitrogen and phosphorus from the wastewater in the water storage device.

[0024] As can be seen from the above technical solution, the present invention provides a sludge electro-dewatering system based on a ring electric field, which has the following advantages compared with the prior art:

[0025] In the sludge pretreatment stage, the present invention adds graphite to the sludge to be treated and crushes and stirs it to make the sludge and graphite mix evenly, thereby improving the dewatering performance of the sludge and increasing the efficiency of subsequent dewatering.

[0026] This invention first removes most of the free water and some interstitial water from the sludge using a mechanical dewatering unit, reducing the sludge's moisture content. Then, an electro-dewatering unit further reduces the initial sludge cake's moisture content by electro-dewatering under a ring-shaped electric field. This combination of mechanical and electro-dewatering fully leverages the advantages of both technologies, achieving highly efficient and energy-saving sludge dewatering. Furthermore, the electro-dewatering unit employs a ring-shaped electric field, with the outer ring as the anode and the inner ring as the cathode, forming a stable electric field distribution. Water collected at the cathode flows out through openings in the baffle, effectively improving the efficiency and stability of the electro-dewatering process.

[0027] The design of the discharge plate allows the initial mud cake to be easily discharged from below the extrusion cylinder, facilitating subsequent processing. Controlled by the first motor, the discharge plate can move perpendicular to the axial direction of the extrusion cylinder, achieving a continuous and stable discharge process.

[0028] In summary, this invention achieves efficient, energy-saving, and environmentally friendly sludge dewatering through optimized design of multiple stages, including sludge pretreatment, a combination of mechanical and electro-dewatering, conveyor belt transport, and a ring-shaped electric field, demonstrating significant advancements in sludge dewatering. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the unit connection relationship of the present invention;

[0031] Figure 2 This is a schematic diagram of the system structure of the present invention;

[0032] Figure 3 This is a schematic diagram of the annular sleeve structure in this invention;

[0033] Wherein, 1 represents the mixing box, 2 represents the sludge inlet, 3 represents the graphite inlet, 4 represents the sludge agitator, 5 represents the extrusion cylinder, 6 represents the discharge plate, 7 represents the first motor, 8 represents the extrusion plate, 9 represents the second motor, 10 represents the perforated platform, 11 represents the perforated conveyor belt, 12 represents the water storage device, 13 represents the annular sleeve, 14 represents the insulating plate, 15 represents the third motor, 1301 represents the cathode, and 1302 represents the anode. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] This invention discloses a sludge electro-dewatering system based on a ring-shaped electric field. See [link to relevant documentation]. Figures 1-2 ,include:

[0036] The sludge pretreatment unit is used to add graphite to the sludge and crush and mix it to obtain a sludge mixture.

[0037] A mechanical dewatering unit is used to mechanically dewater the sludge mixture to obtain an initial sludge cake;

[0038] A cake conveying unit is used to convey the initial cake to an electro-dehydration unit;

[0039] The electro-dehydration unit is used to electro-dehydrate the initial sludge cake under a ring electric field to obtain wastewater and dehydrated sludge cake.

[0040] In this embodiment, the sludge pretreatment unit includes a closed mixing tank 1, a sludge inlet 2, a graphite inlet 3, a sludge agitator 4, and a discharge port. The mixing tank 1 is the core component of the sludge pretreatment unit, used to mix and agitate the sludge and other added materials. The sludge inlet 2 is located at the top of the mixing tank 1 and is used to add the sludge to be treated into the mixing tank 1. The graphite inlet 3 (or other additive inlet) is also located at the top of the mixing tank 1 and is used to add graphite or other additives into the mixing tank 1 to condition the sludge and improve the dewatering rate of the subsequent electro-dewatering process. The sludge agitator 4 is installed at the bottom of the mixing tank 1 and is used to mix and agitate the sludge and additives within the mixing tank 1. Agitation ensures thorough mixing of the sludge and additives, promoting chemical reactions or physical processes and improving the effectiveness of sludge pretreatment. The discharge port is located on the side of the mixing tank 1 and is used to discharge the pretreated sludge from the mixing tank 1. In specific implementations, the discharge port can also be equipped with valves or other control devices to regulate the discharge volume and speed of the sludge.

[0041] The sludge pretreatment unit can effectively mix sludge and additives together and promote chemical reactions or physical processes through stirring, thereby improving the effect of sludge pretreatment.

[0042] The mechanical dewatering unit includes a cylindrical extrusion cylinder 5, a discharge plate 6, and an extrusion plate 8.

[0043] The extrusion cylinder 5 is designed as a cylindrical structure with openings at the top and bottom. A sludge mixture inlet is located on the side wall, allowing the sludge mixture to enter. Several evenly spaced openings are also present on the side wall to release moisture from the sludge during the extrusion process, improving dewatering efficiency. The inner wall of the side wall is lined with a high-strength, highly permeable geotextile, which effectively prevents leakage of the solid portion of the sludge mixture during extrusion while allowing water to pass freely.

[0044] The extrusion plate 8 is located on the upper end face of the extrusion cylinder 5, with one side directly contacting the sludge mixture inside the cylinder 5, ensuring that the extrusion plate 8 can effectively apply pressure to the sludge mixture. A connecting rod is provided on the other side of the extrusion plate 8, which is connected to the second motor 9, allowing the second motor 9 to drive the extrusion plate 8 to move via the connecting rod. When the second motor 9 starts, it drives the extrusion plate 8 to move axially along the extrusion cylinder 5 via the connecting rod. This movement allows the extrusion plate 8 to gradually squeeze the sludge mixture downwards, thereby squeezing out the water, which is then discharged through the openings on the side wall of the extrusion cylinder 5 and the discharge plate 6. When the extrusion plate 8 reaches a predetermined position or squeezes to a predetermined degree, the motor stops working, the squeezing process is complete, and the mechanical dewatering of the sludge mixture is achieved.

[0045] A discharge plate 6 is disposed on the lower end face of the extrusion cylinder 5. The discharge plate 6 contacts but is not fixed to the lower end face of the extrusion cylinder 5. The discharge plate 6 also has several uniformly spaced openings and is lined with high-strength, high-permeability geotextile. The side of the discharge plate 6 is connected to a first motor 7, which drives the discharge plate 6 to move perpendicular to the axial direction of the extrusion cylinder 5. The discharge plate 6 is a key component of the mechanical dewatering unit. It is located on the lower end face of the extrusion cylinder 5 and contacts but is not fixed to it. This design allows the discharge plate 6 to move freely under the drive of the motor, thereby completing the initial discharge of the sludge cake. The discharge plate 6 also has several uniformly spaced openings and is lined with high-strength, high-permeability geotextile, similar to the arrangement on the side wall of the extrusion cylinder 5, both used to release moisture from the sludge during the extrusion process while preventing solid material leakage.

[0046] The side of the discharge plate 6 is connected to the first motor 7. The first motor 7 and the side of the discharge plate 6 are connected via a transmission mechanism such as a chain or rack and pinion, thus converting the rotational motion of the first motor 7 into the linear or reciprocating motion of the discharge plate 6. When the initial mud cake after extrusion and dewatering needs to be discharged, the first motor 7 starts, driving the discharge plate 6 to move axially perpendicular to the extrusion cylinder 5. Because the discharge plate 6 contacts but is not fixed to the lower end face of the extrusion cylinder 5, the discharge plate 6 can move smoothly, discharging the dewatered initial mud cake from the extrusion cylinder 5. This design allows the mechanical dewatering unit to conveniently and quickly discharge the initial mud cake after completing the mechanical dewatering process, improving the efficiency of the entire processing flow.

[0047] The sludge cake conveying unit is located below the mechanical dewatering unit and includes an opening platform 10 and an opening conveyor belt 11. Its main function is to receive and convey the initial sludge cake after mechanical dewatering, and at the same time collect and store the wastewater generated during the dewatering process.

[0048] The perforated platform 10 is the main structure supporting the perforated conveyor belt 11. The perforated conveyor belt 11 is mounted on the perforated platform 10 and in close contact with it to ensure stable conveying. The upper surface of the perforated conveyor belt 11 is covered with a high-strength, highly permeable geotextile to allow moisture to pass through. The main function of the perforated conveyor belt 11 is to receive the initial mud cake discharged from the mechanical dewatering unit and convey it to subsequent processing units.

[0049] The water storage device 12 is located below the perforated platform 10. Its function is to receive and store the sewage seeping from the perforated platform 10 and the perforated conveyor belt 11. The sewage includes sewage discharged from the mechanical dewatering unit and the electric dewatering unit, as well as sewage seeping out when the mud cake moves on the perforated conveyor belt 11.

[0050] The electro-dehydration unit is an annular sleeve 13 with an open bottom, see [reference]. Figure 3 The outer ring is the anode 1302, connected to the positive terminal of the power supply, and the inner ring is the cathode 1301, connected to the negative terminal of the power supply. The upper end face of the annular sleeve 13 is an insulating plate 14. One side of the insulating plate 14 is fixedly connected to the outer and inner rings, and the other side of the insulating plate 14 is connected to a third motor 15. The third motor 15 drives the annular sleeve 13 to move downward, so that the annular sleeve 13 covers the initial mud cake for electro-dehydration. The lower end of the outer ring is an open structure, and the lower end of the inner ring is provided with a baffle. The baffle is fixed to the inner ring, and both the inner ring and the baffle have several uniform openings and are lined with high-strength, high-permeability geotextile.

[0051] The electro-dehydration unit is an annular sleeve 13 with an open bottom. Its outer ring is the anode 1302, and its inner ring is the cathode 1301. This structure forms an annular electric field environment for electro-dehydration of the initial mud cake. The upper end face of the annular sleeve 13 is an insulating plate 14. One side of the insulating plate 14 is fixedly connected to the outer and inner rings to ensure the safe and stable operation of the electric field. The other side of the insulating plate 14 is connected to a third motor 15. Driven by the third motor 15, the insulating plate 14 and the annular sleeve 13 can move up and down.

[0052] The lower end of the outer ring is open to facilitate the entry of mud cake, while the lower end of the inner ring is equipped with a baffle fixed to the inner ring to prevent mud cake from entering. Both the inner ring and the baffle have several evenly spaced openings and are lined with high-strength, highly permeable geotextile. These openings and the geotextile allow water to pass through, enter the inner ring, and then drain out through the openings in the baffle and the geotextile, achieving dehydration.

[0053] During the electro-dehydration process, the initial mud cake is moved below the electro-dehydration unit, and the third motor 15 is started, driving the annular sleeve 13 downwards so that it covers the initial mud cake. At this time, an electric field is formed between the anode 1302 and the cathode 1301. Under the action of the electric field, the water in the initial mud cake is discharged, enters the inner ring, and then flows out through the openings in the baffle and the geotextile. When the predetermined dehydration effect is achieved, the third motor 15 stops working, the annular sleeve 13 rises, and the dehydrated mud cake is removed.

[0054] In practice, to improve the efficiency and processing capacity of electro-dehydration, the annular sleeves 13 in the electro-dehydration unit can be configured in multiples, and these annular sleeves 13 are distributed above the perforated conveyor belt 11 at preset intervals. The simultaneous operation of multiple annular sleeves 13 can achieve parallel processing of the mud cake, greatly improving the efficiency of electro-dehydration.

[0055] In other embodiments, the system further includes a wastewater treatment unit for recovering nitrogen and phosphorus from the wastewater in the water storage device 12. In specific implementations, appropriate recovery methods can be selected based on the content and form of nitrogen and phosphorus in the wastewater. For example, nitrate nitrogen can be converted into gaseous nitrogen gas through nitration-reduction reaction. Phosphorus can be precipitated as an insoluble precipitate by adding chemical agents (such as polyaluminum chloride, polyaluminum sulfate, etc.), and then removed from the wastewater through solid-liquid separation. This invention does not limit the specific nitrogen and phosphorus recovery methods.

[0056] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0057] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A sludge electro-dewatering system based on a ring-shaped electric field, characterized in that, include: The sludge pretreatment unit is used to add graphite to the sludge and crush and mix it to obtain a sludge mixture. A mechanical dewatering unit is used to mechanically dewater the sludge mixture to obtain an initial sludge cake; A cake conveying unit is used to convey the initial cake to an electro-dehydration unit; The electro-dehydration unit is used to electro-dehydrate the initial mud cake under a ring electric field to obtain wastewater and dehydrated mud cake; The sludge pretreatment unit includes a closed mixing tank. The top of the mixing tank is equipped with a sludge inlet and a graphite inlet. The bottom of the mixing tank is equipped with a sludge agitator. An outlet is provided on the side of the mixing tank for introducing the sludge mixture into the mechanical dewatering unit through a pipeline. The electro-dehydration unit is an annular sleeve with an open bottom. The outer ring is the anode and the inner ring is the cathode. The upper end face of the annular sleeve is an insulating plate. One side of the insulating plate is fixedly connected to the outer and inner rings, and the other side of the insulating plate is connected to a third motor. The third motor drives the annular sleeve to move downward, so that the annular sleeve covers the initial mud cake and performs the electro-dehydration process. The lower end of the outer ring is an open structure, and the lower end of the inner ring is provided with a baffle. The baffle is fixed to the inner ring, and both the inner ring and the baffle are provided with several uniform openings and are lined with high-strength and high-permeability geotextile. The system also includes a wastewater treatment unit for recovering nitrogen and phosphorus from the wastewater in the water storage device.

2. The sludge electro-dewatering system based on a ring-shaped electric field according to claim 1, characterized in that, The mechanical dewatering unit includes a cylindrical extrusion cylinder, a discharge plate, and an extrusion plate; The extrusion cylinder is a cylindrical structure with openings at the top and bottom, and several uniform openings are provided on the side wall. The inner wall of the side wall is lined with high-strength and high-permeability geotextile. The side wall is also provided with a sludge mixture inlet. The unloading plate is disposed on the lower end face of the extrusion cylinder. The unloading plate is in contact with but not fixed to the lower end face of the extrusion cylinder. The unloading plate is also provided with several uniform openings and is lined with high-strength and high-permeability geotextile. The side of the unloading plate is connected to the first motor, and the first motor drives the unloading plate to move perpendicular to the axial direction of the extrusion cylinder. The extrusion plate is disposed on the upper end face of the extrusion cylinder. One side of the extrusion plate is in contact with the sludge mixture inside the extrusion cylinder, and the other side is provided with a connecting rod. The connecting rod is connected to a second motor. The second motor drives the connecting rod and the extrusion plate to move axially along the extrusion cylinder, so that the extrusion plate extrudes the sludge mixture inside the extrusion cylinder, thereby achieving mechanical dewatering of the sludge mixture.

3. The sludge electro-dewatering system based on a ring-shaped electric field according to claim 1, characterized in that, The sludge cake conveying unit is located below the mechanical dewatering unit and includes an opening platform and an opening conveyor belt; The perforated conveyor belt is installed on the perforated platform, with the lower end face of the perforated conveyor belt in contact with the perforated platform and the upper end face covered with a high-strength, high-permeability geotextile.

4. The sludge electro-dewatering system based on a ring-shaped electric field according to claim 3, characterized in that, A water storage device is installed below the perforated platform to receive wastewater passing through the perforated conveyor belt and the perforated platform.

Images